The present invention relates to a vertical take-off and landing aircraft for transporting people or loads (cargo) with a plurality of electric motors and propellers that are advantageously identical and redundant and arranged essentially in a surface or plane, wherein an electric motor is allocated to each propeller for driving the propeller, according to the preamble of claim 1.
Such aircraft are also known according to the designation VTOL for “vertical take-off and landing.” In the present description, the designation “multicopter” is also used as an alternative. In this context the invention is not restricted to aircraft that are controlled by a pilot inside the aircraft, but also relates to aircraft that can be used for the remote-controlled or autonomous transport of corresponding cargo.
Vertical take-off aircraft with a plurality of propellers or rotors are known. As drives, internal combustion engines were regularly used, which, however, could be controlled only slowly and relatively imprecisely. In this way, fast attitude control for the aircraft is practically impossible. For this reason, for example, for known aircraft in the form of helicopters, a blade adjustment of the rotors is provided for faster attitude control. This leads, however, to a significantly increased expense in terms of construction and costs and to considerable wear during operation.
In the field of model making, aircraft with four or six propellers and an electric drive are known in which the attitude control in flight is achieved through fast changes in the rotational speed of the electric drives being used. A simple upscaling of this design for the construction of aircraft that can carry people, however, would leave to considerable safety risks, because if only one electric motor were to fail, it would no longer be possible to control the aircraft. Also, for larger-scale propellers, the necessary time period for changing the thrust would be so large that fast attitude control would also not be possible.
From GB 2 468 787 A, an aircraft is known that is constructed fundamentally like a conventional fixed-wing aircraft. To be able to take off and land vertically, it has a plurality of electric jet engines that are formed as ducted fan engines and can be pivoted. The advantage of higher static thrust of the ducted fan engines is counteracted by significant disadvantages, for example, the increased manufacturing expense with tight tolerances and the relatively poor aerodynamics for forward flight.
From US 2006/0266881 A1, an aircraft according to the class is known with a plurality of electrically driven rotors or propellers. The described aircraft has propellers that lie on different planes, wherein the circular area of the rotors overlap. This can also cause aerodynamic disadvantages. For driving the propellers, electric motors with brushes and gears are used and this means a relatively high amount of wear and maintenance expense. In addition, the pilot alone is responsible for the attitude control of the known aircraft by means of the control stick, which basically rules out use of the aircraft for persons without appropriate training and experience.